The present invention relates to optoelectronic devices and, more particularly, to organic light emitting devices (organic EL devices). More specifically, the present invention relates to substantially stable organic EL devices, such as, for example, organic EL devices with a half-life in embodiments of, for example, not less than about 1,000 hours, that is the device possesses a half-life of at least about 1,000 hours even at which devices in embodiments are stable high temperatures, such as from about 70xc2x0 C. to about 100xc2x0 C., and moreover, which devices are not substantially adversely affected by high temperatures; and yet, more specifically, possess a combination of desirable features, such as (1) an excellent stability, such as, for example, a half-life of at least 1,000 hours from an initial luminance of about 100 cd/m2 at elavated temperatures of about 80xc2x0 C. to 100xc2x0 C.; (2) an excellent quantum efficiency, such as, for example, an external quantum efficiency of at least about 4 percent when operated at a luminance of 100 cd/m2; and (3) an improved color purity, such as, for example, color coordinates of about 0.679, 0.319 on the C.I.E. chart.
An organic electroluminescent (EL) device can be comprised of a layer of an organic luminescent material interposed between an anode, typically comprised of a transparent conductor, such as indium tin oxide, and a cathode, typically a low work function metal such as magnesium, calcium, aluminum, or the alloys thereof with other metals. The EL device functions on the primary principle that under an electric field, positive charges (holes) and negative charges (electrons) are respectively injected from the anode and cathode into the luminescent layer and undergo recombination to form excitonic states which subsequently emit light. A number of organic EL devices have been prepared from a laminate of an organic luminescent material and electrodes of opposite polarity, which devices include a single crystal material, such as single crystal anthracene as the luminescent substance as described, for example, in U.S. Pat. No. 3,530,325, the disclosure of which is totally incorporated herein by reference. These types of devices are believed to require excitation voltages on the order of 100 volts or greater.
An organic EL device with a multilayer structure can be formed as a dual layer structure comprising one organic layer adjacent to the anode supporting hole transport, and another organic layer adjacent to the cathode supporting electron transport and acting as the organic luminescent zone of the device. Examples of these devices are disclosed in U.S. Pat. Nos. 4,356,429; 4,539,507; 4,720,432, and 4,769,292, the disclosures of which are totally incorporated herein by reference, wherein U.S. Pat. No. 4,769,292, the disclosure of which is totally incorporated herein by reference, discloses, for example, an organic EL device comprising three separate layers, a hole transport layer, a luminescent layer, and an electron transport layer, which layers are laminated in sequence and are sandwiched between an anode and a cathode, and wherein a fluorescent dopant material is added to the emission zone or layer whereby the recombination of charges results in the excitation of the fluorescent material. In some of these multilayer structures, such as, for example, organic light emitting devices described in U.S. Pat. No. 4,720,432, the disclosure of which is totally incorporated herein by reference, the organic light emitting device further comprises a buffer layer interposed between the hole transport layer and the anode. The combination of the hole transport layer and the buffer layer forms a dual-layer hole transport region, reference S. A. Van Slyke et al., xe2x80x9cOrganic Electroluminescent Devices with Improved Stability,xe2x80x9d Appl. Phys. Lett. 69, pp. 2160-2162, 1996, the disclosure of which is totally incorporated herein by reference.
There have also been attempts to obtain electroluminescence from organic light emitting devices containing mixed layers, for example, layers in which both the hole transport material and the emitting electron transport material are mixed together in one single layer, see, for example, Kido et al., xe2x80x9cOrganic Electroluminescent Devices Based On Molecularly Doped Polymers,xe2x80x9d Appl. Phys. Lett. 61, pp. 761-763, 1992; S. Naka et al., xe2x80x9cOrganic Electroluminescent Devices Using a Mixed Single Layer,xe2x80x9d Jpn. J. Appl. Phys. 33, pp. L1772-L1774, 1994; W. Wen et al., Appl. Phys. Lett. 71, 1302 (1997); and C. Wu et al., xe2x80x9cEfficient Organic Electroluminescent Devices Using Single-Layer Doped Polymer Thin Films with Bipolar Carrier Transport Abilitiesxe2x80x9d, IEEE Transactions on Electron Devices 44, pp. 1269-1281, 1997. In a number of these devices, the electron transport material and the emitting material can be the same or the mixed layer can further comprise an emitting material as a dopant. Other examples of organic light emitting devices which are formed of a single organic layer comprising a hole transport material and an electron transport material can be found, for example, in U.S. Pat. Nos. 5,853,905; 5,925,980; 6,114,055 and 6,130,001, the disclosures of which are totally incorporated herein by reference. As indicated in the article by S. Naka et al., these single mixed layer organic light emitting devices are generally less efficient than multilayer organic light emitting devices. These devices, which include only a single mixed layer of a hole transport material, such as NBP (N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine), and an emitting electron transport material, such as Alq3 (tris (8-hydroxyquinoline) aluminum), are believed to be unstable and to have poor efficiency. The instability of these devices is believed to be caused by the direct contact between the electron transport material in the mixed layer and the hole injecting contact comprised of indium tin oxide (ITO), which results in the formation of an unstable cationic electronic transport material, and the instability of the mixed layer/cathode interface, see H. Aziz et al., Science 283, 1900 (1999), the disclosure of which is totally incorporated herein by reference. In addition, the single mixed layer may result in high leakage currents and hence poor efficiency, see Z. D. Popovic et al., Proceedings of the SPIE, Vol. 3176, xe2x80x9cOrganic Light-Emitting Materials and Devices IIxe2x80x9d, San Diego, Calif., Jul. 21-23, 1998, pp. 68 to 73, the disclosure of which is totally incorporated herein by reference.
While recent progress in organic EL research has elevated the potential of organic EL devices for widespread applications, the operational stability of current available devices may in some instances be below expectations. A number of known organic light emitting devices have relatively short operational lifetimes before their luminance drops to some percentage of its initial value. Providing interface layers as described, for example, in S. A. Van Slyke et al., xe2x80x9cOrganic Electroluminescent Devices with Improved Stability,xe2x80x9d Appl. Phys. Lett. 69, pp. 2160-2162, 1996, and doping as described, for example, in Y. Hamada et al., xe2x80x9cInfluence of the Emission Site on the Running Durability of Organic Electroluminescent Devicesxe2x80x9d, Jpn. J. Appl. Phys. 34, pp. L824-L826, 1995, may perhaps increase the operational lifetime of organic light emitting devices for room temperature operation, however, the effectiveness of these organic light emitting devices deteriorates for high temperature device operation. In general, the device lifetime can be reduced by a factor of about two for each 10xc2x0 C. increment in the operational temperature. Moreover, at high temperatures, the susceptibility of the organic light emitting devices to degrade is increased as described, for example, in Zhou et al., xe2x80x9cReal-Time Observation of Temperature Rise and Thermal Breakdown Processes in Organic Leds Using an IR Imaging And Analysis Systemxe2x80x9d, Advanced Materials 12, pp 265-269, 2000, which further reduces the stability of the devices. As a result, the operational lifetime of these organic light emitting devices at a normal display luminance level of about 100 cd/m2 is limited, for example, to about a hundred hours or less at temperatures of about 60xc2x0 C. to about 80xc2x0 C., reference J. R. Sheats et al., xe2x80x9cOrganic Electroluminescent Devicesxe2x80x9d, Science 273, pp. 884-888, 1996, and also S. Tokito et al., xe2x80x9cHigh-Temperature Operation of an Electroluminescent Device Fabricated Using a Novel Triphenylamine Derivativexe2x80x9d, Appl. Phys. Lett. 69, 878 (1996).
Aspects of the present invention relate to an organic light emitting device comprising
(i) a first electrode;
(ii) a region comprising a mixture of (1) a tertiary aromatic amine, (2) a metal oxinoid, and (3) a red emitting material represented by 
wherein X is a carbon C atom or a nitrogen N atom or optionally oxygen or sulfur; R1, R2 and R3 are appropriate groups, such as each being independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, and substituted aryl; M is a divalent, trivalent or tetravalent metal;
(iii) a second electrode;
(iv) an optional protective element coated on at least one of the first and second electrodes, wherein one of said first and second electrodes is a hole injection anode, and one of said electrodes is an electron injection cathode; and at least one of
(v) a hole transport region situated between the anode and the region (ii), and wherein the hole transport region optionally includes a buffer layer; and
(vi) an electron transport region situated between the cathode and the region (ii), and wherein said red emitting component is present in an amount of from 1 to about 40 weight percent based on total weights of components in region (ii); organic light emitting device wherein the red emitting material is 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum (II) (PtOEP); an organic light emitting device wherein the tertiary aromatic amine is N,N,Nxe2x80x2,Nxe2x80x2-tetraaryl benzidine; an organic light emitting device wherein said amine is N,N,Nxe2x80x2,Nxe2x80x2-tetraaryl benzidine selected from the group consisting of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) and N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD); and optionally wherein the metal oxinoid is tris(8-hydroxyquinoline) aluminum (Alq3); an organic light emitting device wherein there is at least one of said hole transport region comprising a component or compound selected from the group consisting of tertiary aromatic amines, porphyrins, and indolocarbazoles; and said electron transport region containing a component selected from the group consisting of metal oxinoids, stilbenes, triazines, porphyrins, and quinolines; an organic light emitting device wherein region (ii) comprises from about 20 weight percent to about 80 weight percent of said tertiary aromatic amine, and from about 80 weight percent to about 20 weight percent of said metal oxinoid; and wherein the weight percents are based on the total weight of components comprising the mixed region; an organic light emitting device wherein region (ii) comprises from about 35 weight percent to about 65 weight percent of said tertiary aromatic amine; from about 65 weight percent to about 35 weight percent of said metal oxinoid; and from about 3 weight percent to about 30 weight percent of said red emitting component, and wherein the total thereof is about 100 weight percent; an organic light emitting device wherein region (ii) comprises from about 5 weight percent to about 25 weight percent of said red emitting material; an organic light emitting device wherein there is at least one of A. said component of the hole transport region (v) and the tertiary aromatic amine comprising region (ii) are similar; and B. wherein the electron transport region (vi) and the metal oxinoid comprising region (ii) contain similar components; an organic light emitting device wherein at least one of A. said hole transport region (v) and the tertiary aromatic amine comprising region (ii) are dissimilar; and B. said electron transport region (vi) and the metal oxinoid comprising the mixed region are dissimilar; an organic light emitting device wherein an electron transport region is present, and wherein the electron transport region comprises at least two layers; an organic light emitting device wherein a first layer of the electron transport region contacts the mixed region, and which first layer comprises a component selected from the group consisting of metal oxinoids, and quinolines; and a second layer of the electron transport region contacts the cathode, and which second layer comprises a component selected from the group of metal oxinoids, phthalocyanines, and triazines; an organic light emitting device wherein the first layer contains a metal oxinoid of tris(8-hydroxyquinoline) aluminum (Alq3), bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), or a quinoline of 1,4-bis(4-phenylquinolin-2-yl)benzene, 4,4xe2x80x2-bis(4-phenylquinolin-2-yl)-1,1xe2x80x2-biphenyl (TA); and the second layer contains a metal oxinoid comprising tris(8-hydroxyquinoline) aluminum (Alq3) or bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), a phthalocyanine of copper phthalocyanine (CuPc), or a triazine of 4,4xe2x80x2-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-p-tolyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-m-tolyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-p-methoxyphenyl-1,3,5-triazinyl)]-1,1 xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-m-methoxyphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, or 2,4,6-tris(4-biphenylyl)-1,3,5-triazine; an organic light emitting device wherein said hole transport region (v) is present, and wherein the hole transport region comprises at least two layers; an organic light emitting device wherein a first layer of the hole transport region contacts the anode, and which first layer comprises a porphyrin; and wherein a second layer of the hole transport region contacts the mixed region, and which second layer comprises a component selected from the group of tertiary aromatic amines and indolocarbazoles; an organic light emitting device wherein the first layer comprises copper phthalocyanine; and the second layer comprises a tertiary aromatic amine of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) or N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD), or an indolocarbazole of 5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole or 2,8-dimethyl-5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole; an organic light emitting device wherein a hole transport region (v) is present, and wherein the hole transport region comprises a layer comprised of a mixture of (i) from about 25 weight percent to about 99 weight percent of a porphyrin, and (ii) from about 75 weight percent to about 1 weight percent of an aromatic tertiary amine or an indolocarbazole; an organic light emitting device wherein there is present at least one of (1) an anode comprising a layer comprised of indium-tin-oxide, and (2) a cathode comprising a layer selected from the group consisting of (i) a layer comprised of Mg and Ag; (ii) a layer comprised of Al; (iii) a layer comprised of indium-tin-oxide; and (iv) a layer comprised of a mixture of an organic compound of Mg and Ag; an organic light emitting device wherein the cathode further comprises an alkaline metal or a compound thereof; an organic light emitting device wherein the alkaline metal is selected from the group consisting of Li, Na, K and Cs; an organic light emitting device wherein the thermal protective element is present, and which thermal protective element comprises a layer of SiO, SiO2 or mixtures thereof; an organic light emitting device wherein region (ii) has a thickness of from about 5 nanometers to about 500 nanometers; the hole transport region has a thickness of from about 5 nanometers to about 250 nanometers; and/or the electron transport region has a thickness of from about 5 nanometers to about 100 nanometers; an organic light emitting device comprising
(i) an anode of indium-tin-oxide with a thickness of from about 30 to about 300 nanometers coated on a substrate, the anode and the substrate being capable of transmitting at least about 70 percent of radiation of wavelength equal to or longer than about 400 nanometers;
(ii) a hole transport region contained on the anode and comprised of a compound selected from the group consisting of copper phthalocyanine (CuPc), N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB), N,Nxe2x80x2-bis(p-biphenyl)-N, Nxe2x80x2-diphenyl benzidine (biphenyl TPD), 5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole, and 2,8-dimethyl-5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole; and which region has a thickness of from about 5 nanometers to about 100 nanometers;
(iii) a mixed region situated on the hole transport region and comprised of (1) from about 35 weight percent to about 65 weight percent of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) or N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD); (2) from about 65 weight percent to about 35 weight percent of tris(8-hydroxyquinoline) aluminum or bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum; and (3) from about 5 weight percent to about 25 weight percent of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum (II) (PtOEP), and wherein all weight percentages are based on the total weight of components comprising the mixed region, and wherein the thickness of the mixed region is from about 50 nanometers to about 150 nanometers;
(iv) an electron transport region situated on the mixed region, and comprised of tris(8-hydroxyquinoline) aluminum (Alq3) or bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), and wherein the thickness of the electron transport region is from about 5 nanometers to about 50 nanometers;
(v) a cathode situated on the electron transport region, and comprised of one of (1) a layer comprising a Mg:Ag alloy or Al of a thickness of from about 50 nanometers to about 500 nanometers; and (2) a first layer comprised of from about 40 volume percent to about 55 volume percent of Mg; from about 2 volume percent to about 10 volume percent of Ag and from about 55 volume percent to about 40 volume percent of Alq3; wherein the thickness of the first layer is from about 100 nanometers to about 600 nanometers, and which first layer is coated with a second layer of a thickness of from about 50 nanometers to about 500 nanometers comprising a metal or a metal alloy; and
(vi) a protective layer situated on the cathode comprised of SiO, SiO2 or mixtures thereof of a thickness of from about 100 nanometers to about 1,000 nanometers; an organic light emitting device comprised of
(i) an anode of indium-tin-oxide with a thickness of from about 30 to about 300 nanometers, which anode is coated on a substrate, the anode and the substrate being capable of transmitting at least 70 percent of radiation of wavelength longer than about 400 nanometers;
(ii) a hole transport region present on the anode and which region contains a component selected from the group consisting of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB), N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD), 5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole, and 2,8-dimethyl-5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole, and which region further contains a buffer layer contacting the anode of copper phthalocyanine, wherein the thickness of the buffer layer is from about 10 nanometers to about 30 nanometers and the thickness of the hole transport region is from about 5 nanometers to about 20 nanometers greater than the thickness of the buffer layer;
(iii) a mixed region situated on the hole transport region comprised of (1) from about 35 weight percent to about 65 weight percent of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) or N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD); (2) from about 65 weight percent to about 35 weight percent of tris(8-hydroxyquinoline) aluminum or bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum; and (3) from about 5 weight percent to about 25 weight percent of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum (II) (PtOEP), wherein all weight percentages are based on the total weight of components comprising the mixed region, and wherein the thickness of the mixed region is from about 50 nanometers to about 150 nanometers;
(iv) an electron transport region situated on the mixed region of tris(8-hydroxyquinoline) aluminum (Alq3) or bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), wherein the thickness of the electron transport region is from about 5 nanometers to about 50 nanometers;
(v) a cathode situated on the electron transport region comprised of one of (1) a layer comprised of Mg:Ag alloy or Al of a thickness of from about 50 nanometers to about 500 nanometers; and (2) a first layer comprised of from about 40 volume percent to about 55 volume percent of Mg; from about 2 volume percent to about 10 volume percent of Ag and from about 55 volume percent to about 40 volume percent of Alq3, wherein the thickness of the first layer is from about 100 nanometers to about 600 nanometers; and which first layer is coated with a second layer of a thickness of from about 50 nanometers to about 500 nanometers comprising a metal or a metal alloy; and
(vi) an optional thermal layer situated on the cathode comprised of SiO, SiO2 or mixtures thereof of a thickness of from about 100 nanometers to about 1,000 nanometers; an organic light emitting device comprising
(i) an anode of indium-tin-oxide with a thickness of from about 30 to about 300 nanometers, which anode is coated on a substrate, the anode and the substrate being capable of transmitting at least about 70 percent of radiation of wavelength longer than about 400 nanometers;
(ii) a hole transport region situated on the anode comprised of at least one component selected from the group consisting of copper phthalocyanine (CuPc), N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB), N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD), 5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole, and 2,8-dimethyl-5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole; and which region has a thickness of from about 5 nanometers to about 100 nanometers;
(iii) a mixed region situated on the hole transport region comprised of (1) from about 35 weight percent to about 65 weight percent of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) or N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD); (2) from about 65 weight percent to about 35 weight percent of tris(8-hydroxyquinoline) aluminum or bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum; and (3) from about 5 weight percent to about 25 weight percent of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum (II) (PtOEP) wherein all weight percents are based on the total weight of components comprising the mixed region, and wherein the thickness of the mixed region is from about 50 nanometers to about 150 nanometers;
(iv) an electron transport region situated on the mixed region comprising (1) a first layer of a thickness of from about 5 nanometers to about 25 nanometers contacting the mixed region wherein the first layer is comprised of tris(8-hydroxyquinoline) aluminum (Alq3), bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), 1,4-bis(4-phenylquinolin-2-yl)benzene, or 4,4xe2x80x2-bis(4-phenylquinolin-2-yl)-1,1xe2x80x2-biphenyl (TA); and (2) a second layer of a thickness of from about 5 nanometers to about 25 nanometers contacting the cathode, wherein the second layer is comprised of tris(8-hydroxyquinoline) aluminum (Alq3), bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), copper phthalocyanine (CuPc), 4,4xe2x80x2-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-p-tolyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-m-tolyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-p-methoxyphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-m-methoxyphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, or 2,4,6-tris(4-biphenylyl)-1,3,5-triazine;
(v) a cathode situated on the electron transport region comprised of one of (1) a layer comprising Mg:Ag alloy or Al of a thickness of from about 50 nanometers to about 500 nanometers; and (2) a first layer comprised of from about 40 volume percent to about 55 volume percent of Mg; from about 2 volume percent to about 10 volume percent of Ag; and from about 55 volume percent to about 40 volume percent of Alq3, wherein the thickness of the first layer is from about 100 nanometers to about 600 nanometers, and coated with a second layer of a thickness of from about 50 nanometers to about 500 nanometers comprising a metal or a metal alloy; and
(vi) a thermal protective component situated on the cathode comprised of SiO, SiO2 or mixtures thereof of a thickness of from about 100 nanometers to about 1,000 nanometers; an organic light emitting device comprising
(i) an anode of indium-tin-oxide with a thickness of from about 30 to about 300 nanometers, which anode is coated on a substrate, the anode and the substrate being capable of transmitting at least about 70 percent of radiation of wavelength longer than about 400 nanometers;
(ii) a hole transport region present on and in contact with the anode comprised of a component selected from the group consisting of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB), N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD), 5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole, and 8-dimethyl-5,11-di-naphthyl-5,11-dihydroindolo[3,2-b]carbazole; and which region further comprises a buffer layer contacting the anode, and comprised of copper phthalocyanine, wherein the thickness of the buffer layer is from about 10 nanometers to about 30 nanometers; and the thickness of the hole transport region is from about 5 nanometers to about 20 nanometers greater than the thickness of the buffer layer;
(iii) a mixed region situated on the hole transport region comprised of (1) from about 35 weight percent to about 65 weight percent of N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) or N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD); (2) from about 65 weight percent to about 35 weight percent of tris(8-hydroxyquinoline) aluminum or bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum; and (3) from about 5 weight percent to about 25 weight percent of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum (II) (PtOEP), wherein all weight percentages are based on the total weight of materials comprising the mixed region, and wherein the thickness of the mixed region is from about 50 nanometers to about 150 nanometers;
(iv) an electron transport region situated on the mixed region comprising (1) a first layer of a thickness of from about 5 nanometers to about 25 nanometers contacting the mixed region, wherein this first layer is comprised of tris(8-hydroxyquinoline) aluminum (Alq3), bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), and 1,4-bis(4-phenylquinolin-2-yl)benzene, 4,4xe2x80x2-bis(4-phenylquinolin-2-yl)-1,1xe2x80x2-biphenyl (TA); and (2) a second layer of a thickness of from about 5 nanometers to about 25 nanometers contacting the cathode, wherein the second is comprised of tris(8-hydroxyquinoline) aluminum (Alq3), bis(8-hydroxyquinolato)-(4-phenylphenolato)aluminum (Balq), copper phthalocyanine (CuPc), 4,4xe2x80x2-bis-[2-(4,6-diphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-p-tolyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-m-tolyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, 4,4xe2x80x2-bis-[2-(4,6-di-p-methoxyphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, and 4,4xe2x80x2-bis-[2-(4,6-di-m-methoxyphenyl-1,3,5-triazinyl)]-1,1xe2x80x2-biphenyl, or 2,4,6-tris(4-biphenylyl)-1,3,5-triazine;
(v) a cathode situated on the electron transport region comprised of one of (1) a layer comprised of Mg:Ag alloy or Al of a thickness of from about 50 nanometers to about 500 nanometers; and (2) a first layer comprised of from about 40 volume percent to about 55 volume percent of Mg; from about 2 volume percent to about 10 volume percent of Ag; and from about 55 volume percent to about 40 volume percent of Alq3, wherein the thickness of the first layer is from about 100 nanometers to about 600 nanometers, and coated with a second layer of a thickness of from about 50 nanometers to about 500 nanometers comprising a metal or a metal alloy; and
(vi) a thermal protective element situated on the cathode comprised of SiO, SiO2 or mixtures thereof of a thickness of from about 100 nanometers to about 1,000 nanometers; an organic light emitting device wherein X is oxygen, or sulfur; an organic light emitting device wherein X is an alkyl amino group wherein alkyl contains from about 1 to about 20 carbon atoms; an organic light emitting device wherein X is an aryl imino group wherein aryl contains from about 6 to about 36 carbon atoms; an organic light emitting device wherein R1 and R2 alkyl contain from about 1 to about 20 carbon atoms; and R1 and R2 aryl contain from about 6 to about 36 carbon atoms; an organic light emitting device wherein R3 and R4 alkyl contain from about 1 to about 20 carbon atoms; an organic light emitting device wherein R5, R6, R7 and R8 alkoxy contain from about 1 to about 20 carbon atoms and alkyl contains from about 1 to about 20 carbon atoms; an organic light emitting device wherein the protective layer is comprised of a silicon dioxide or a silicon oxide; an organic light emitting device wherein the hole transport region is present; the electron transport region is present; or the hole transport region and the electron transport region are present; an organic light emitting device wherein each of the regions comprises from about 1 to about 20 layers; an organic light emitting device wherein each of the regions comprises from about 1 to about 5 layers; an organic light emitting device wherein each of the regions is from about 1 to about 3 layers; an organic light emitting device wherein each of the regions is from about 2 to about 4 layers; an organic light emitting device wherein each of the regions is one layer; an organic light emitting device wherein the emitter amount is from about 0.1 to about 5 weight percent; an organic light emitting device wherein the red emitter amount is from about 0.2 to about 2 weight percent; an organic light emitting device wherein the M is aluminum, gallium, zinc or indium; a device comprising a first electrode, a second electrode, a region comprised of a mixture of a tertiary aromatic amine, a metal oxinoid and an emitting compound; an optional protective layer, and at least one of a hole transport region and an electron transport region, wherein one of the first and the second electrode is a cathode and wherein one is an anode; wherein the hole transport region is situated between the anode and the mixed region; wherein the electron transport region is situated between the cathode and the mixed region; wherein the light emitting compound is present in an amount of from 1 to about 40 weight percent and wherein the emitting compound is 
wherein X is a suitable component like a carbon C atom or a nitrogen N atom, or optionally oxygen or sulfur; R1, R2 and R3 are each independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, aryl, and substituted aryl; and M is a divalent, trivalent or tetravalent metal; and which devices possess in embodiments thereof (i) excellent and high stability, such as, for example, a half-life of, for example, about 1,000 hours from an initial luminance of 100 cd/m2 at temperatures of about, for example, 80xc2x0 C. to 100xc2x0 C., (2) a high quantum efficiency, such as, for example, an external quantum efficiency of at least about 4 percent when operated at a luminance of 100 cd/m2, and (3) an excellent color purity, such as, for example, color coordinates of about 0.679, 0.319 on the C.I.E. chart; an EL device comprised in sequence of
(i) a first electrode, which can be an anode or a cathode;
(ii) a mixed region comprising a mixture of (1) a tertiary aromatic amine, (2) a metal oxinoid, and (3) a green emitting material as illustrated in copending application U.S. Ser. No. (not yet assignedxe2x80x94D/A1581), the disclosure of which is totally incorporated herein by reference, or a red emitting material encompassed by Formula I 
wherein, for example, X is a C atom or an N atom; R1, R2 and R3 are each independently selected from the group consisting of hydrogen; alkyl; aryl; with substituents of, for example, recognized donor and acceptor groups wherein R1 and R2 may be combined together to form a fused ring; and M is a divalent, trivalent or tetravalent metal;
(iii) a second electrode, which can be a cathode or an anode;
(iv) a thermal protective layer coated on one of the first and second electrodes, wherein one of the first and second electrodes is a hole injection anode, and one of the electrodes is an electron injection cathode, and wherein the organic light emitting device further comprises at least one of
(v) a hole transport region interposed between the anode and the mixed region, wherein the hole transport region optionally includes a buffer layer; and
(vi) an electron transport region interposed between the cathode and the mixed region, wherein region throughout refers to at least one layer, and more specifically, from one to about 10 layers; and an EL device where the tertiary aromatic amine is N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) or N,Nxe2x80x2-bis(p-biphenyl)-N,Nxe2x80x2-diphenyl benzidine (biphenyl TPD) and the metal oxinoid is tris(8-hydroxyquinoline) aluminum (AlQ3).
The organic light emitting devices can be utilized in various devices, such as displays, that typically are operated over a broad range of temperature conditions. The operational stability at high temperature conditions provided by the organic light emitting devices of this invention enables in embodiments thereof use at high temperature applications for extended periods of time. In addition, the organic light emitting devices of the present invention can provide red emission with increased efficiency and excellent color purity.